Electric meter.



No. 703,051. Pafenfdlunem, |902'.-

1 T. A. Emson.

ELECTRIC METER.

(Application filed Oct. l5, 1900.)v

3 Sheeis-Shee L (No Motief.)

Y www Mmmm@ l WnNEssEs VWM ATTORN EYS;v

No. .763,05L A Paten-red :une 24, |902 T; A. EmsoN. 4 ELECTRIC METER. (Application lel Oct. 15, kOOJ 3 Sheets-Sheet 2.

(No Model.)

T. A. EDISON.

ELECTRIC METER. (Appxicmdn med om. is. moo.:

Patented Jun 24,' ii902.

(Nu Mpdel.)- 3 Sheetsf-Shi 3,

Iriventqt A tt lys.

UNITED STATES PATENT OFFICE.

THOMASA. EDISON, OF LLEVVELLYN PARK, NEI/V JERSEY.

ELECTRIC METER.

SPECIFICATIN forming para of Letters Patent No. 703,051, 'dated June 24, 1902.

Application filed October 15, 1900. Serial No.33l034. (No model) `(Case No. 1,0472) of which the following is a description.

My' invention relates to various new and useful improvements in electric meters of the type described in my patent dated October 23, 1900, No. 660,293, wherein is employed a constant speed-motor, which drives a register at a speed substantially proportional to the vention an electric motor the speed of which was maintained constant by a 'centrifugal speed-governor, the motor driving one element of a frictional variable-speed gearing,the other element of which was connected to the register, and the relative positions of such gear elements being determined by an ampere-indicator directly influenced by the current to be measured. With said meter I provided means for periodically separating the two cooperating elements of the variable-speed gearing in order that the ampere-indicator might be free to respond to variations in the consumed current and not be subject tothe frictional engagement of such cooperating elements.

My present improvements are designed to simplify the construction and increase the eficiency of an electric meter of the speciiic type described in said patent.

The improvements relate, first, to the construction of a centrifugal speed-governor for the elect-ric motor, by means of which its eficiency and durability will be increased; second, to improvements in the construction and arrangement of the ampere or other current indicator; third, to the use of cut-ont devices for short-circuiting the ampere-indicator in the event of destructively-large currents in the circuit; fourth, to an improved manner of connecting the register with the constantspeed motor, whereby during periodic intervals the current-indicator will be free to adjust itself to changes in the load absolutely independent of any friction lother than the negligible friction of the knife-edge pivots of In my said patent I de' lscribed as a specific embodiment'of the in,-

the scale-beam; fth, to the employment of means whereby may be overcome a slight error due to the magnetic inertia, which Ihave found to exist in meters of this type in the registration of the first-increments of current; sixth, to the doing away in an electric meter 'of magnetic, electric, or elastic constants, which are necessarily variable, and the employment of gravity only as a constant, and, finally, to various other'detailsin the construction and operation, all as willl be more fully hereinafter set forth and claimed.

In order that'my invention may be better understood, attention is directed to the accompanyin g drawin gs,forminga part of this speciiication, and in which- Figure 1 isa front elevation, partly in section, showing the operative parts of my improved meter; Fig. 2, a plan View thereof; Fig. 3, a detail view of the cam and part of the register; Fig. 4, a rear View of the cam; Fig. 5, a side view thereof; Fig. 6, a front end tview thereof; Fig. 7, a cross-sectional View thereof; Fig. '8, a diagram of the motorcircuit-s, and Fig. 9 a detail View of the bottom bearing of the armature-shaft of the electric motor.

In all of 'the above views corresponding parts are represented by the same numerals of reference.

1 represents an electric motor of any suitable type, the armature 2 of which is mounted on a vertical shaft 3L This shaft is stepped on a block 4, of phosphor-bronze or other hard material, which is received in a vertically-adjustable cup 5 (see Fig. 9) for holding oil, so as to lubrioate the shaft, as will be understood. The armature-shaft 3 passes through a bearing 6, carried by a suitable base 7, which in turn is secured to a back plate or bed S. An arm 9 is secured to the armature-shaft below the bearing 6 and carries at its free ends the bell-cranks 10, having weights 11 at their lower ends. The short arms of the bell-cranks are provided with buffers or friction-pads 12, made,`preferably, of fiber, and said pads cooperate with a disk 13, secured to the under side of the base and made of hard smooth material, preferably a glass disk cemented to said base. As the speed of the armature 2 increases the centrifugal weights 1l will swing outwardly, en-

IOO

gaging the friction-pads 12 with the surface 13, so as to impose a resistance to the rotative effect, whereby a practically constant speed of the motor-armature will be secured. Mounted in suitable bearings on the base 7 is a shaft 14, which is rotated by the armatureshaft 3 by any suitable gearing, such as a worm 15 and gear 16. This shaft carries a barrel 17, to the periphery of 4which is secured a cam 18 of the generally triangular form shown. The cam 18 may be separated from the barrel 17 or be integral therewith, as will be understood. Obviously so much of the barrel 17 as is not coincident with the cam 18 may be dispensed With. Furthermore, the barrel 17 may be entirely dispensed with and the cam supported in other ways from the shaft 14. Said cam is curved longitudinally on the arc of a circle struck from the pivot of a scale-beam 19. The pivots of this beam are formed by knife-edges 20, bearing on lugs 21, carried by an arm 22, which arm is rigidly secured to the plate 8. Depending from the beam 19 is an arm23,which works in an opening 24 in the arm 22, and carried by the arm 23 at its lower end is a vregister 25 of any suitable and appropriate type. This register may be operated from a gear 26, driven, for instance, through a worm connection from a vertical shaft 27, as shown in Fig. 3. The shaft 27 is preferably provided near its lower end with a gear 28, which is engaged with and driven by a worm 29 on a shaft 30. The end of the shaft 30 opposite the worm 29 is carried in a slotted bearing 31 and rests upon an adjusting-screw 32. The engagement between the worm 29 and gear 28 is such as to permit the free end of the shaft 30 to Vmove slightly in the slotted bearing 31 and away from the adjustingscrew 32 without cramping or otherwise affecting the driving operation between the shafts 30 and 27. Carried by the shaft 30 is a friction-wheel 33, which is adapted to be periodically engaged and rotated by the cam 18 as the latter passes beneath said frictionwheel. As the friction-wheel is caused to engage diierent portions of said cam under the effect of the current to be measured, as

,will be described, said wheel' will be driven I through different arcs to operate the register y intermittently at a speed proportional to the current consumed.

The register 25 and the elements carried 'thereby are preferably counterbalanced by tional to the current consumed when the coils to be referred to are energizedV by such current. The ampere-indicator coils just inentioned are' wound, preferably, on a copper tube 39, which is suitably carriedfby a support 40, secured to the plate 8. The meter illustrated is intended specifically for use on a three- Wire system, in which case each of the outside wires (see Fig. 8) is in series with one solenoid-coil or set of solenoid-coils which are wound on the tube 39. Preferably with the three-wire meter theselcoils are arranged in the four sets 4l, 42, 43, and 44, as shown in Fig. 1, each set being formed of a single layer of comparatively coarse insulated wire helically wound in position.' The outside coil 41 is connected with the inside coil 44, as shown, and said coils are arranged in series, for eX- ample, with the negative main, as shown, while the inner coils 42 and 43 are connected together and are arranged in series with the other main. By this arrangement the combined magnetic effect on the core 36 of the coils 4l and 44 is substantially equal to the combined magnetic effect thereon of the coils 42 and 43, whereby corresponding movements of the core 36 will be produced by a corresponding current in either the positive or negative main. This arrangement also enables me to shorten the vertical dimension of the solenoid and to thereby reduce the length and weight of the core. The solenoid coils referred to may be supported upon the tube 39 by means of a split collar44, as shown, whereby said coils may be also vertically adjustable with respect to said tube.' I find in practice that an am pere-indicator comprising one or more solenoid-coils and an overweighted core movable freely therein produces a proportionately-shorter movement of the core when the first increment of current traverses the coil or coils than when added increments the current are caused to traverse said coil or coils, owing to magnetic inertia of the core. Although this error could be compensated by properly changing the form of the cam 18, as will be obvious, I prefer to correct itby the employment of a corrective auxiliary coil45,made of very fine wire and wound, preferably, on the outside of the ampere-coils and to arrange the same, as shown, in series with the motor `1 across the line from one of the outside wires to the neutral wire, as shown, or between both of the outside wires, as will be obvious. I find in practice that the minute current necessary to operate the motor 1 and which traverses the corrective coil 45 tends to overcome the magnetic inertia'of the core 36,-so that the latter becomes proportionately responsive to the currents infiuencing the ampere coil or coils. In order to prevent injury to the delicate moving parts of the meter should the latter be subject to a destructive current, as might occur in the case of a short circuit beyond the meter, I prefer to employ a magnetic cut-out device 46 for each outside main in a three-wire circuit or for one of the mains IOO IIO

esoliof Whiolgwhenfattrected-,is'edapted tol-r closet-shunts@ morne seam'p'eeecois, y

the me Yeif',.-tl1ve" insgneticeutout or .cut-outs A meer( of e. twow're; oircnitLeud the armature 4f?- ci;

each 'shunt including .'ljie `sedgfarinature,a$ shown'.

In'orderto limit the lextreme fl'ove'-,

ments .of the"` corset., I. preferably. employ-'t2 elestcbuffefrs 49;-,uii1ichiftrecarried by arms.

. 50,"secu`red to the" plete@ above below.

.said core,.es.siiow`n.j W.

' The operationfof my'iinprovedfineter lsf s follows: Normally the .ifi."icti ":si{vilfieeli 32*l yW-ill be almost in engagement with theinarrcw'e'nd. ofl the cem 1S. ,vVhi ,themete'r is properly. connected upv for .nsel'rw'ith thclifniotorinA Uneuh` tiple, the latter will commence to. operate untilV its speed reaches., the desiredpoint,

whereupon such speed will. be maintained constant byV the centrifugal speed-gmforno rA described. The slight' current which traverses-.the motor also iniiuences the corrective, coil 45,110 overcome the magnetic inertie of the core 36so that' when any current iniu. ences theampere-coils ou4 either or both the outside 'mains the core 3.6 will be etti-atleted-to` the proper proportioimtey extent, swinging the scale-beam .19 on its pivot and causing the friction-.wheel to beengeged by the properpert of the cam 18 as to give the desired rate of. This Amovement of the scalebe measuredcen take piece withoutlresistf ance during that portion .of the retentionl 'of the sheft 14 willen the cam is' Withdrawn from engagement Withthe friction-Wheel, as will be understood. At this time it will loeobvi-l ons that the empere-indioatorfwill befree to', adjust itself to tirer current to be measured" absolutely independentofeny friction 'other than the negligible-friction imposed by the.

knife-edge Apivots '20.. At; each rotation of thesheft 14, therefore,the caan 18fwill2engege the friction-wheel 33 tomove the saine n Y in a, smalleror larger. are, according to. they current. to be 1neesnred,andin-thisieng fre-@ ment `bt-atween the cam and the Ifriction-Wheel the latter will be slightly elevated to lift'the lfree end of the shaft Ojfrom theadjustng-l screw` 32, the shaft falling back. upon such ajnsting-screw after the cam has ceased to engage the -'rietion-wheel.. Byy thus reguleting theedjustingj-screw yso the-tfthe lower edge .ofl the friction-wheel will be slightly be low the planebfthe oamlS, whereby the late ter will slightlyelevate thefrictiomwheel at.' each engagement. therewith, l fdo away with." the necessitylof` securing a, constant and deli-l cete adjustment'between tbe Gain end'lfriction-Wheel andxat the same time prevent ythe possibility of 'soy lost motion due toord.,

nary weer of; either oi said elementsl By winding* the .solenoid ,-Jcoilse upon a; copperJ tube; as explained, VI dempen or ineke-slug-` gish. the movements of the core-36, (Without,

however, eecting the accuracy of- `the, indii cator,) owing to the generation of Foegult" currents. in 'said tube .due to variation-sin the strength of seid coils. produced byr changes in @the terrestre be-,.meessred When 2f. des current traverses the circuit, as :tney tbeicesfe offs short circuitv beyond vw'iiifeiese one 'or boer ofthe 'shunts 4s te copperltube 39, due' totliepresence inthe ampere coilor ceilsof such e, destructive our?y Zdainpen'ing ory making {sluggishvthe move- 'mentsof the core, the latter. .wonldbe moved Lcould beshorgt-.circnited .and there would, be denger'of the'jpivots of the seelefoeem lbe-` 'ranged Patent, is as follows: Y

with-en overbelenced' .beern,ed core connected toone endv of said beam, a stationery coil surronndingseid core/,end traversed bytbeeurlrent tobbe measuree registereonnected to and movable with the beam, end a. friction- 'ui'th said. register, of a, cam with whichseid friction-wheel periodically cooperates, andan electric. motor connected-'across the tine lfor stsntially as set forth..

2. in en yelectric meter,

to one end of seid beam, e. stationery eoilsnnr-` rounding seid coreend treversedby the?takin'-l .rentfto be measured, e register connecte` to and movebie with the beam, end: frictionwheel movable Awith the .besmand connectedV with said. register, -of e oam'withwhich said frietion-wheei periodically coperetes,en eleetric motor `connected across the line for rotating seid cem et econstant speed, end en aurL-j' substantially as set forth.; i

with en overbelauced ,beaxmeoore connectedv to one end of seidbeem', e, ststionergirv coilsurn rent to-be measured, sregisterconne'cted to tric motor'connectedaoross the line. forfrotet-` 'ing 'seid ca-met con-stent speed, 'asien' iur# beam.A ,if Vineens wereA notyemployed for ito its full extent under the inuenceof thev destructive lcurrents beforey the` ooilorcoils.

wlggeelmovsble 'with the beem and connected vthe .ctnnbination:l with an overbelenced beam, e core connected' iliarycoi-l of highresistance-surreundingthe 3; in en' electric motori-the combination.

-end'movable with the beam?, and "Se friction! wheel f inovebleWithftbe-besm and', connectedl -lwitiisaid register, "of seem With' -wiiicb-sid" .friction`wheel periodiceily cooperate7s,e.nelec1 f short-circuit the ampere-coils. By reason *etl 5 VVthe''generetion of Foucault currents invftherent, the. dempnn'g. eeot referred." to "will inl this .movement the L comingdislodged or themeterotherwise de- Having new described inylinvention, VWirst I claim es new, .enddesire to secure by Letters'V l.v In' en eecjtric meter, the combination ICIS rotating said cem .et s constentspeed, subir.

producing saturation orpel-arization thereof,- "i E:

-roundingseidcoreand treversedby tlefcurl'f` iiiarycoilof high resistance surroundingthe co're for overccmingmagnetic inertia without stan "ally as set forth.

4. fn an electric'meter, thenconi'bination with a beam a current-indicator for moving said beam, a magnetic cut-out'in series with ,the current-indicator for short-circuiting the lattentvhen .a destructive current traverses the cut-out, and a register connected to and movable with the' beam, of a variable-speed gearing, one element of whichis movable with, the register, and a motor for operating the other element of said gearing, substantiallyV as and for'the purposes set forth.

5. In an electric meter, the combination with a 4current-indicator having a movable element, a beam to which said elementis connected, elastic buffers for limiting they ex-l treme movementsof said element,- and-fa' lieg" vister, of a variable-speed gearing the position of whose elements is determined by the position of said beam,and a motorfor driving the register through snidvariable-s'peed gearing,

substantially as set forth'.

6. In anelectric meter, the'dcombination .with a beam, a core connected to, one end of said beam, a copper Atube surrounding said core and in which the core is freely movable, an ampere-coil Wound on the tube and traversed bythe current tok be lmeasured, andy -a register,ofazvariable-speed gearing the po# sition of whose-'elements is determined by the position of said beam, and a motor for 'drivling the register through said 'variable-speed` gearing, substantially asset forth.

7. In an electric meter, the combination witha beam, a core connected to one end of said beam, a copper tube. surrounding said core and in which the fc'ore-is freely movable, an ampere-coil'woundcoh thentube and traversed by the current tobe 1neasured', elastic buers for limiting-thev` extreme movements of said core,V and a "register, of a. variable; speed gearing the position of AWhose'elements is determined Yby, the position' of ,'rsaid beam, and a'motor for driving the register through said variable-speedv gearing, substantially as set forth. g

8. In a three-Wire meter, the combination with a beam, a co're connected' to one end of said beam, a copper tube surrounding vsaidcore and within which the core is' freely movable, four ampere-coils .Wound` helica'll'ylandf concentrically upon said itu-be, the outer and inner coils being connectedin-series'with one of the outside mains and the-'two inner coils being connected in serieswith the other outside main, and a regster,"of avaliable-speed 4 gearing the position of Whose elements is djetermined by the position of said beam, and amotor for driving said register thronghf'said; variable-speed gearing, substantially' as set forth.

9. Iii-an electric meter, the combination with abeam, a core connected to one end of `the core-fdr overcoming the magnetic inertia nected t'o one end ofsaidv beam,- a coil for in- `fluencing the core traversed by the current to vtreme movements of said core, substantially said beam, an ampere-coil surrounding the core vand ltraversed by thecurrent to be measured, and a register, of a variable-speed gearfor driving lsaid register through said variablespeed gearing', and an auxiliary coi-l inclosin g thereof without producing saturation or polarization, substantially asset forth.

10. In an electric meter, the combination with a beam, a core yconnected to one end of said beam, an ampere-coil surrounding the core and traversed by the current to be measured, and a register, of a variable-speed gearing the position of Whoseelements is` determined bythe position of said beam, a motor fordriving said register through said variablespeed gearing, and a stationaryauxiliary coil .inclosing the core and in series with said motor, substantially as set forth.

1l. In an electric meter, the combination with a beam, an ampere-indicator the movable element of which is connected with said beam, saidindicator including a coil traversed by the current to'be measured, a register, and a motor for operating saidl register, of la 'magnetic cut-outl arranged to close'a shunt around theampere-coil whensaid cutout is influenced by an abnormal current, substantially as set forth. l2.A In an electric meter,.thecombination with a register,`a'n ampere-indicator, and a variable-speedA geari-ngltlie position of "whose elements is determined by said indicator, of a' constant-speed motorfor driving `the register through the variable -speed gearing, and a centrifugal speed-regulator for said motor employing a Weighted bell-crank carrying a friction-padfwhich coperates with a glass friction-surface, substantially as set forth.

13. In an electric meter, the combination pere-indicator comprising a beam, a cere con-k nected to one' end of said beam, a coil for in-,

viiuencing the core traversed by the current to;r be measured, and a copper tube on which the coil is wound'and in which the core is freely7 movable, substantially as set forth.

14. In an electric meter, the combination with a register and a driving-motel', of an ampere-indicator comprising a beam, a core conbe measured, a copper tube on which the coil is Wound andin Which the core is freely mov- V able, and elastic buiers for limiting the ex.

as setforth.

structive current isv traversing the coil, and ac v lool- 15?v In an electric meter, -the combination y,With a register and a'drivingmotor,.of an ams pere-indicator comprising a beam, a core concopper tube on which tlhe coil is Wound and withouoproducing polarization or saturation in which the core is freely movable, substanthereof, substantially as set forth. m-

tially' as set forth. l This specification signed and witnessed this 16. In v au electric meter, the combination 28th day of September, 1900.

5 with a'register and a motor for operating the THOMAS A. EDISON. same, of an ampere-indicator comprising a Wit-messes: l l l coil, a. core, andan auxiliary coil for snbjeefr FRAN L. DYER,

ing the core tol an initial magnetizing eieo; l JNO. TAYLOR. 

